How to: Replace a Brake Light Switch on a Mercedes W202

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A common(ish) fault on W202 C-Classes and W210 E-Classes is the BAS/ASR light appearing on the dashboard. Mine has been coming on and off for a couple of weeks as and when it seems to want to.

There are a number of possible reasons for this but the cheapest and easiest to fix is a faulty brake light switch.

The brake light switch actually has two functions and two sets of wires coming away from it. One simply switches the brake lights on and off and the other runs off into the loom to tell the car if there is a fault and to turn the light on. The brake lights on the car work perfectly so I’m hoping that it is just a little fault in that second function.

To get to the brake light switch you will have to remove this panel from the the underside of the steering wheel. Most of the screws holding it on are fairly obvious but there are a couple that are hiding.

The first one is just behind the parking brake.

The second is just behind the bonnet release.

You will also have to remove this vent. To remove it turn the plastic screw 90 degrees and give it a pull.

With that out of the way the panel should drop down. I’m sure some of you can wiggle it out past the parking brake lever and bonnet release lever but it gave me enough room hanging there.

Behind that column is a bit of a spiders web of wires and stuff. Do you see the grey wire “202 290 07 85”? The brake light switch is just above the thing that that wire plugs into.

Literally right above it. You see the black box that the red and black wiring harness is going into? That’s what we need!

To remove it just grab hold of the box and turn it 90 degrees clockwise. It will pop out straight away.

Now we just have to remove the wires. It is easier to remove the large plug first. It has two wings on either side that need to be pushed in and then give it a good pull. The second will pull out easy enough. Don’t worry about which way around they go as they can only fit one way.

The old and the new!

Putting it back together is literally the reversal of removal. Now all there is to do is to start the car, make sure your brake lights are working and make sure the light on the dashboard has gone out!

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